US3747282A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for polishing wafers
Assignee: JOHN CRANE HOUDAILLE Inc A CORP OF
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Filing: 1971-11-29
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Granted: 1973-07-24
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Expires: 1991-11-29
Abstract
Abstract An improved vacuum chuck for holding a thin fragile workpiece, such as a silicon wafer used as an electronic component, as the workpiece is being polished. The improved chuck has a removable and replaceable ring surrounding the workpiece to hold the workpiece in the event of an accidental loss of vacuum, and the chuck is grooved to distribute the differential pressure across the wafer over the entire wafer to avoid distortion due to localized pressure differences. The increased holding power of the chuck permits the use of higher downward pressures on the workpiece which speeds the polishing action both by increased abrasion and by increased chemical erosion which is accelerated by the higher heat of friction.
Inventors
- 👤 E Katzke
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 15:14
CPC Classifications
B; B25; B25B; B25B11/00; B25B11/005; Y; Y10; Y10T; Y10T279/00; Y10T279/11
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
134 words
A fixture for holding a thin workpiece while a surface of the workpiece is being abraded, said fixture comprising a rigid support having a surface of predetermined contour against which the said workpiece surface is adapted to be held, said fixture surface having concentric grooves formed therein separated by lands, said grooves having a width between lands in the range of 0.050 inch to 0.54 inch, said lands having a width in the range of 0.008 inch to 0.012 inch, and said workpiece having a thickness in the range of 0.003 inch to 0.008 inch, said workpiece being circular in form concentrically disposed over said grooves and extending beyond the last groove by approximately the width of a land, and means connecting the relieved portion of the fixture surface to a source of vacuum.
Claim 2
Dependent Claim
134 words
A fixture for holding a thin workpiece while a surface of the workpiece is being abraded, said fixture comprising a rigid support having a surface of predetermined contour against which the said workpiece surface is adapted to be held, said fixture surface having concentric grooves formed therein separated by lands, said grooves having a width between lands in the range of 0.050 inch to 0.54 inch, said lands having a width in the range of 0.008 inch to 0.012 inch, and said workpiece having a thickness in the range of 0.003 inch to 0.008 inch, said workpiece being circular in form concentrically disposed over said grooves and extending beyond the last groove by approximately the width of a land, and means connecting the relieved portion of the fixture surface to a source of vacuum.
Claim 3
Dependent Claim
73 words
A fixture as described in claim 1, said fixture having further a groove concentric with the disc and of a diameter loosely to surround said disc, and removable means in said groove and extending above the surface of the fixture but below the upper surface of the wafer to be abraded and adapted to hold the wafer against lateral movement along the surface of the fixture while holding said wafer over said grooves.
Claim 4
Dependent Claim
20 words
A fixture as described in claim 2, said removable means comprising a ring of polytetrafluoroethylene frictionally held in said groove.
References Cited (Backward Citations)
US2405417A
Cited
US3627338A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-23 | 1977-01-22 | 1977-07-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-23 | 1981-01-22 | 1981-07-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-23 | 1985-01-22 | 1985-07-24 | $7700.00 | Window Closed / Lapsed |